* Replace screenshot in README.md
The screenshot previously featured at the top of the README.md was that of the old Qt-based UI. This new image is of the modern SDL2-based UI, and more accurately reflects how Vanilla currently appears.
* Change to screenshot of Mario Kart 8 in Vanilla
* Add FindFFmpeg.cmake, to fix Ubuntu FFmpeg errors
* Rename "finders" to "cmake"
* Add Qt minimum version message
* I am an idiot, fix CMakeLists.txt
* Fix unicode, to fix monochrome text-style for sync icons
* Fix text-style for backspace and empty
* Expand compilation instructions
- Add build packages to dependencies list for each OS
- Consolidate two commands into "mkdir build && cd build"
- Add command for installing Vanilla
* Add FindFFmpeg.cmake, to fix Ubuntu FFmpeg errors
* Rename "finders" to "cmake"
* Add Qt minimum version message
* I am an idiot, fix CMakeLists.txt
* Fix unicode, to fix monochrome text-style for sync icons
* Fix text-style for backspace and empty